JP2015031875A - Mesh structure and mesh sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a miniaturized mesh structure.SOLUTION: A mesh sheet 10 comprises: a rugged structure layer 30 having a rugged surface 31 formed by fine small projections 32; and a mesh structure 20 including a conductor 25 disposed on a valley bottom 34 serving as an intermediate part between the fine small projections 32 out of the rugged surface 31.

Description

  The present invention relates to a mesh structure formed in a stitch shape and a mesh sheet including the mesh structure.

  Conventionally, a mesh structure formed in a stitch shape and defining an opening region has been used in various fields.

  As a widely known example, a conductive mesh structure having visible light permeability is used as a transparent conductive member forming an electromagnetic wave shielding material (electromagnetic wave shielding sheet) or a touch panel sensor disclosed in Patent Documents 1 and 2. It has been. While such a mesh structure is formed using a metal material that is opaque per se, it is used as an electromagnetic shielding material (electromagnetic shielding sheet) or a touch panel sensor used in many applications, for example, a display device. In such applications, it is desired to be sufficiently invisible. In particular, when the pattern of the mesh structure is visually recognized, not only does the transmittance decrease, but also causes problems such as uneven shading, flickering, and moire when superimposed on other members, for example. Therefore, the mesh structure is preferably miniaturized to such an extent that it can be made invisible.

  As another example of the mesh structure, a catalyst carrier is exemplified. For example, Patent Document 3 discloses an example in which a mesh structure is used as a catalyst carrier for a hydrogen reformer of a fuel cell. Even in such a mesh structure, it is required to refine the mesh structure.

JP-A-11-121974 WO2007 / 114076 Special table 2008-523565

  On the other hand, the inventors of the present invention, as a result of intensive research, can produce a fine mesh structure by using a concavo-convex structure layer having a concavo-convex surface formed by minute protrusions. I found out. The present invention is based on such knowledge. That is, an object of the present invention is to provide a refined mesh structure and a mesh sheet including a refined mesh structure and an uneven structure layer. .

The mesh sheet according to the present invention is:
An uneven structure layer having an uneven surface formed by minute protrusions;
A mesh structure including a conductor provided on a valley bottom portion between the minute projections on the uneven surface.

In the mesh sheet according to the present invention,
The average line width of the conductor of the mesh structure is 5 nm or more and 500 nm or less,
You may make it the average of the space | interval of adjacent microprotrusion be 1000 nm or less.

  The mesh sheet | seat by this invention WHEREIN: The said microprotrusion may be provided in the space | interval which becomes below the shortest wavelength of a visible light band.

  The mesh sheet | seat by this invention WHEREIN: The said conductor may be provided also on parts other than the said valley bottom part of the said uneven surface.

The first mesh structure according to the present invention comprises:
Comprising a conductor defining an open area;
The average line width of the conductor is 5 nm or more and 500 nm or less,
The average interval between adjacent opening regions is 1000 nm or less.

The second mesh structure according to the present invention is:
A conductor body located on a virtual plane and defining an open area;
A conductor extension extending from the conductor body, and
The conductor extension part is a position facing a normal direction to the virtual plane with respect to an opening region defined by a portion of the conductor main body part connected to the conductor extension part. Is extended.

In the second mesh structure according to the present invention,
The average line width of the conductor body is 5 nm or more and 500 nm or less,
The average interval between adjacent opening regions may be 1000 nm or less.

  According to the present invention, the mesh structure can be sufficiently miniaturized.

FIG. 1 is a plan view illustrating an example of a pattern of a mesh structure, for explaining an embodiment of the present invention. FIG. 2 is a cross-sectional view along the normal direction of a mesh sheet having a mesh structure. FIG. 3 is a perspective view showing an uneven structure layer of the mesh sheet of FIG. FIG. 4 is a plan photograph showing an example of the uneven surface of the uneven structure layer. FIG. 5 is a schematic diagram for explaining a method for producing a mesh structure. FIG. 6 is a plan view for explaining a method for producing a mesh structure. FIG. 7 is a cross-sectional photograph for explaining a method for producing a mesh structure. FIG. 8 is a graph showing the reflectance of the mesh structure. FIG. 9 is a diagram showing a display device including an electromagnetic wave shielding sheet made of a mesh sheet. FIG. 10 is a schematic diagram showing a touch panel device including a touch panel sensor made of a mesh sheet.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings other than the photographs attached to the present specification, for the sake of illustration and ease of understanding, the scale and the vertical / horizontal dimensional ratio are appropriately changed and exaggerated from those of the actual ones.

  In the present specification, the terms “sheet”, “plate”, and “film” are not distinguished from each other only based on the difference in names. For example, “sheet” is a concept that includes members that can be called plates and films, and therefore “mesh sheets” are distinguished from members called “mesh plates” and “mesh films” only by the difference in names. I don't get it.

  In addition, the sheet “surface (plate surface, film surface)” is a sheet-like member (plate-like) that is the target when the target sheet-like (plate-like, film-like) member is viewed as a whole and globally. It refers to the surface that coincides with the plane direction of the member or film-like member. In the present embodiment, the sheet surface of the mesh sheet, the sheet surface of the uneven structure layer of the mesh sheet described later, and the sheet surface of the transparent base material of the mesh sheet described later are parallel to each other.

  Furthermore, as used in this specification, the shape and geometric conditions and the degree thereof are specified. For example, terms such as “parallel”, “orthogonal”, “identical”, length and angle values, etc. Without being bound by meaning, it should be interpreted including the extent to which similar functions can be expected.

<< Mesh sheet and mesh structure >>
As shown in FIG. 1, the mesh structure 20 is a mesh-like member that defines a large number of opening regions 21. As shown in FIGS. 1 and 2, the mesh structure 20 is made of a conductor 25 that defines the opening region 21, for example, a metal. The conductor 25 includes a conductor main body 26 extending in a curved or linear shape. Note that the conductor main body 26 does not necessarily define the periphery of any of the opening regions 21 in all the portions, and may include a broken portion whose end is located in the opening region 21. .

  The mesh structure 20 described here is formed using an uneven structure layer 30 described later. As shown in FIG. 3, the concavo-convex structure layer 30 has a concavo-convex surface 31 formed by fine protrusions 32 provided at, for example, a nano-order interval d1. Here, “small” of the microprojections 32 means that the mesh structure 20 is fine enough to make the mesh structure 20 sufficiently small as compared with the conventional mesh structure, and is nano-order. The projections provided at intervals are sufficiently included in the microprojections. The mesh structure 20 is formed on the uneven surface 31 using the uneven surface 31. Specifically, as shown in FIG. 2, the conductor main body portion 26 of the conductor 25 is provided on the valley bottom portion 34 that becomes the minute protrusion 32 on the uneven surface 31. And the mesh structure 20 demonstrated here is refined | miniaturized significantly compared with the conventional product, and functions usefully in various uses.

  In particular, in the mesh structure 20 described here, the average of the line width w2 of the conductor main body 26 of the conductor 25 is 5 nm or more and 500 nm or less, and the average of the distance d2 between the adjacent opening regions 21 is 50 nm or more and 1000 nm. It can be as follows. According to the mesh structure 20 in which the average of the line width w2 of the conductor main body 26 of the conductor 25 is 5 nm or more and 500 nm or less and the average of the distance d2 between the adjacent opening regions 21 is 1000 nm or less, The mesh structure 20 cannot be resolved with the eyes.

  By the way, each dimension and shape of the mesh structure 20 such as the line width w2 of the conductor 25 and the distance d2 between two adjacent opening regions 21, and each dimension and shape of the concavo-convex structure layer 30 described later are determined by atomic force. It can identify using a microscope (Atomic Force Microscope; AFM) or a scanning electron microscope (Scanning Electron Microscope: SEM). In addition, each dimension and shape of the mesh structure 20 and each dimension of the concavo-convex structure layer 30 to be described later are calculated by calculating an average value by examining the entire area of the target mesh structure 20 and the concavo-convex structure layer 30. It is not necessary to specify, and in actuality, the area that is expected to reflect the overall tendency of the object to be investigated (such as the line width w2 of the conductor 25 and the interval d2 between two adjacent open regions 21). Can be identified by calculating the average value by examining the number considered to be appropriate in consideration of the degree of variation of the object to be investigated. The values specified in this way can be handled as the average value of the line width of the conductor 25 and the average value of the distance between two adjacent opening regions 21. For example, in the mesh structure 20 manufactured by the manufacturing method described later with the value described immediately before as a target, 30 points included in a 30 mm × 30 mm region are measured with a microscope, and the average is calculated. The line width of the body 25, the size of the opening region 21, and the like can be specified.

  A general mesh structure is formed by forming a metal film on a transparent substrate by, for example, vapor deposition, sputtering, foil transfer, coating, etc., and using this metal film as a mask with a desired photoresist pattern. An etching method, a method of exposing and developing a conductive photosensitive agent (for example, an emulsion in which silver halide grains are diffused) into a desired pattern, or a conductive ink (for example, conductive in which conductive metal particles are dispersed) Ink) can be formed on a transparent substrate by a method such as a method of printing a desired pattern on a transparent substrate. However, the mesh structure 20 in which the average value of the line width w2 of the conductor main body 26 of the conductor 25 and the average value of the distance d2 between two adjacent opening regions 21 are set in the fine range described above is as follows. These conventional methods cannot be manufactured.

  In addition, the inventors of the present invention can not only provide the mesh structure 20 having a useful effect by itself due to its fine structure, but also the concavo-convex structure in a state where it is combined with the concavo-convex structure layer 30. It has been found that due to the organic relationship with the layer 30, excellent effects can be obtained. Below, the mesh structure 20 which comprises a part of the mesh sheet 10 is also demonstrated by demonstrating the mesh sheet 10 containing the mesh structure 20 and the uneven structure layer 30. FIG.

  As described above, the mesh sheet 10 includes the concavo-convex structure layer 30 having the concavo-convex surface 31 formed by the microprotrusions 32 and the conductive portion provided on the valley bottom 34 between the microprotrusions 32 on the concavo-convex surface 31. A mesh structure 20 including a body 25. Further, the mesh sheet 10 shown in FIG. 2 further includes a transparent base material 15 laminated with the concavo-convex structure layer 30. Hereinafter, the transparent base material 15, the uneven structure layer 30, and the mesh structure 20 will be described in this order.

<Transparent substrate 15>
As the transparent substrate 15, a known transparent substrate can be appropriately selected and used, and is not particularly limited. Examples of the material used for the transparent body 15 include a transparent resin and a transparent inorganic material. Examples of the transparent resin include acetyl cellulose resins such as triacetyl cellulose, polyester resins such as polyethylene terephthalate and polyethylene naphthalate, olefin resins such as polyethylene and polymethylpentene, acrylic resins, polyurethane resins, and polyethers. Examples include sulfone, polycarbonate, polysulfone, polyether, polyetherketone, acrylonitrile, methacrylonitrile, cycloolefin polymer, and cycloolefin copolymer. On the other hand, examples of the transparent inorganic material include glass such as soda glass, potash glass, and lead glass, ceramics such as PLZT, quartz, and fluorite.

  In the combination of the mesh structure 20 and the concavo-convex structure layer 30, excellent permeability can be one useful feature of the mesh sheet 10 as described later. From this viewpoint, the visible light transmittance of the transparent substrate 15 is preferably 80% or more, and more preferably 90% or more.

  In the present specification, “transparent” means that the visible light transmittance is 50% or more. In addition, the visible light transmittance referred to in the present specification is measured using a spectrophotometer (manufactured by Shimadzu Corporation “UV-3100PC”, JISK0115 compliant product) within a measurement wavelength range of 380 nm to 780 nm. , Specified as an average value of transmittance at each wavelength.

  The thickness of the transparent substrate 15 can be appropriately set according to the application of the mesh sheet 10 and is not particularly limited, but is usually 20 to 5000 μm, and the transparent substrate 15 is supplied in the form of a roll, Although it does not bend to the extent that it can be wound, it may be either bent by applying a load or not bent completely.

  The configuration of the transparent substrate 15 is not limited to the configuration consisting of a single layer, and may have a configuration in which a plurality of layers are laminated. When it has the structure by which the several layer was laminated | stacked, the layer of the same composition may be laminated | stacked, and the several layer which has a different composition may be laminated | stacked. Moreover, when the transparent base material 15 and the uneven | corrugated structure layer 30 are formed from a different material, the primer for improving the adhesiveness of the transparent base material 15 and the metal thin film 30, and by extension, wear resistance is extended. A layer may be formed on the transparent substrate 15. This primer layer has adhesion to both the transparent substrate 15 and the uneven structure layer 30 and is preferably transparent. As a material for the primer layer, for example, a material selected from a fluorine-based coating agent, a silane coupling agent, and the like can be used as appropriate. Examples of commercially available fluorine-based coating agents include Fluorosurf FG-5010Z130 manufactured by Fluoro Technology, and examples of commercially available silane coupling agents include Durasurf Primer DS-PC-3B manufactured by Harves. Is mentioned.

<Uneven structure layer>
Next, the uneven structure layer 30 will be described. As shown in FIGS. 3 and 4, the concavo-convex structure layer 30 has a concavo-convex surface 31 formed by minute protrusions 32.

  The concavo-convex surface 31 of the concavo-convex structure layer 30 is formed by minute protrusions 32 arranged at intervals d <b> 1 along the sheet surface of the concavo-convex structure layer 30. As will be described later, the uneven surface 31 of the uneven structure layer 30 is used to form the mesh structure 20. From the viewpoint of miniaturizing the mesh structure 20, it is preferable that the distance d1 between the minute protrusions 32 forming the uneven surface 31 is miniaturized. Furthermore, when the present inventors have conducted intensive research, the distance d1 between the minute protrusions 32 forming the uneven surface 31 is formed by the minute protrusions 32 arranged at an interval d1 that is equal to or shorter than the shortest wavelength in the visible light band. It has been found that the concavo-convex structure layer 30 can exhibit a useful function related to the function of the mesh structure 20. That is, as described later, the mesh structure 20 formed on the concavo-convex surface 31 is used as the mesh sheet 10 together with the concavo-convex structure layer 30 without being taken out from the concavo-convex structure layer 30, so that only the mesh structure 20 is used. It is possible to achieve more useful effects than the above. From this point, in the following example, an example in which the minute protrusions 32 are arranged at intervals equal to or shorter than the shortest wavelength in the visible light band will be described.

  Here, the shortest wavelength in the visible light band indicates the shortest wavelength in the visible light band in an environment where the mesh structure 20 or the mesh sheet 10 including the mesh structure 20 is used. Therefore, when only light from a light source limited in an environment where the mesh structure 20 or the mesh sheet 10 is used exists, the shortest wavelength of visible light emitted from the light source is the visible light here. In other cases, 380 nm is adopted as the shortest wavelength of the visible light band in this case.

  The concavo-convex structure layer 30 having the concavo-convex surface 31 in which the minute protrusions 32 are arranged at the interval d1 that is equal to or shorter than the shortest wavelength in the visible light band functions as a so-called moth-eye structure. Therefore, the uneven surface 31 exhibits an extremely excellent antireflection function and exhibits a very high transmittance. Specifically, the visible light transmittance of the concavo-convex structure layer 30 or the visible light transmittance of the laminate including the concavo-convex structure layer 30 and the transparent substrate 15 is preferably 80% or more, and 90%. It is more preferable that it is above. Moreover, it is preferable that the reflectance by 5 degree regular reflection on the uneven surface 31 of the uneven structure layer 30 is 0% or more and 0.3% or less, more preferably 0.1% or less. preferable. Then, if the uneven structure layer 30 is formed as described below, such characteristics can be realized. In addition, the reflectance of the regular reflection referred to in the present specification is a value measured in accordance with JIS Z8722 using a spectrophotometer V-7100 manufactured by JASCO and an automatic absolute reflectance measurement unit VAR-7010. .

  The concavo-convex structure layer 30 can be a layer containing a resin, and can be a layer made of a cured product of the resin composition. The resin composition used for forming the concavo-convex structure layer 30 contains at least a resin and, if necessary, other components such as a polymerization initiator. Examples of the resin used for forming the concavo-convex structure layer 30 include ionizing radiation curable resins such as acrylate, epoxy, and polyester, thermosetting resins such as acrylate, urethane, epoxy, and polysiloxane, and acrylate. Various materials such as thermoplastic resins such as polyesters, polyesters, polycarbonates, polyethylenes, and polypropylenes, and molding resins in various curing forms can be used.

  As the resin used for forming the concavo-convex structure layer 30, an ionizing radiation curable resin is preferable in terms of excellent moldability and mechanical strength of the fine protrusions 32. The ionizing radiation curable resin is a mixture of a monomer having radically polymerizable and / or cationically polymerizable bonds in the molecule, a polymer having a low polymerization degree, and a reactive polymer, depending on the polymerization initiator. It is to be cured. In addition, you may contain a non-reactive polymer. The ionizing radiation means electromagnetic waves or charged particles having energy that can be cured by polymerizing molecules. For example, all ultraviolet rays (UV, UV-B, UV-C), visible rays, gamma rays, X Examples thereof include an electron beam and an electron beam.

  The resin composition further comprises a surfactant, a polymerization initiator, a release agent, a photosensitizer, an antioxidant, a polymerization inhibitor, a crosslinking agent, an infrared absorber, an antistatic agent, and a viscosity modifier as necessary. Further, it may contain an adhesion improver and the like.

  Next, the dimension of the uneven structure layer 30 will be described. The antireflection function by the moth-eye structure is intended to prevent reflection by continuously changing the effective refractive index at the interface between the moth-eye structure and a medium adjacent to the moth-eye structure in the thickness direction. For this reason, the concavo-convex surface 31 of the concavo-convex structure layer 30 is formed by the minute projections 32 arranged along the sheet surface of the concavo-convex structure layer 30 with an interval d1 that is equal to or shorter than the shortest wavelength in the visible light band. Here, the adjacent microprotrusions 32 according to the distance d1 are so-called adjacent microprotrusions 32, which are two protrusions that are in contact with the base portions of the microprotrusions that are the base portions on the transparent substrate 15 side. . In the concavo-convex structure layer 30, the microprojections 32 are arranged in close contact with each other so that when a line segment is created so as to sequentially follow the valleys between the microprojections 32, polygonal regions surrounding the microprojections are obtained in plan view. A mesh-like pattern formed by connecting a large number is produced. The adjacent minute protrusions 32 related to the interval d1 are protrusions that share a part of the line segments constituting the mesh pattern. Further, as shown in FIGS. 2 and 3, the distance d <b> 1 can be a distance between the apexes 33 of the two adjacent minute protrusions 32 along the sheet surface of the mesh sheet 10.

  However, from the viewpoint of imparting an excellent antireflection function to the concavo-convex structure layer 30, it is more preferable that the fine protrusions 32 forming the concavo-convex structure layer 30 are formed as follows. First, the fine protrusions 32 of the concavo-convex structure layer 30 are preferably provided along the sheet surface of the mesh sheet 10 with an interval d1 of 380 nm or less as the shortest wavelength in the visible light band. Further, the height H of the fine protrusion 32 along the normal direction nd to the sheet surface of the mesh sheet 10 is preferably 1500 nm or less and 50 nm or more, and more preferably 1200 nm or less and 80 nm or more. .

  Further, the antireflection performance on the concavo-convex surface 31 of the concavo-convex structure layer 30 is greatly influenced by the aspect ratio of the microprojections 32. The aspect ratio is the ratio of the height H of the microprojections 32 to the width of the microprojections 32. However, in the concavo-convex structure layer 30, the width of the microprotrusions 32 can be handled by replacing the distance d1 between the microprotrusions 32, and thus the aspect ratio is higher than the distance d1 between the microprotrusions 32. It can be handled as the ratio of height H (H / d1). From the viewpoint of imparting the above-described excellent antireflection function to the concavo-convex structure layer 30, the aspect ratio of the microprojections 32 is preferably 1.5 or less and 0.5 or more, and 1.2 or less. More preferably, it is 8 or more.

  The thickness of the concavo-convex structure layer 30 is not particularly limited, but may be 10 to 300 μm as an example. In this case, the thickness of the concavo-convex structure layer 30 means that the microprojections 32 forming the concavo-convex surface 31 of the concavo-convex structure layer 30 from the interface on the transparent base material 15 side of the concavo-convex structure layer 30 as shown in FIG. The height t1 along the normal direction nd to the sheet surface of the uneven structure layer 30 up to the top 33 is meant.

  As already described, various dimensions and shapes of the concavo-convex surface 31 and the microprotrusions 32 of the concavo-convex structure layer 30 are the same as the atomic force microscope (AFM) or the scanning electron microscope (SEM). Can be used to specify. FIG. 4 is an enlarged photograph actually obtained by an atomic force microscope.

  In addition, each dimension of the concavo-convex structure layer 30 does not have to be specified by examining the entire area of the target mesh structure 20 or the concavo-convex structure layer 30 and calculating an average value thereof. Appropriate in consideration of the degree of variation of the objects to be investigated within a section having an area that can be expected to reflect the overall tendency of the objects (interval d2 of the minute protrusions 32, height H of the protrusions, etc.) Can be identified by calculating the average value. For example, in the concavo-convex structure layer 30 made of a cured product of an ultraviolet curable resin produced by shaping an ultraviolet curable resin with the value just described as a target, 30 locations included in a 30 mm × 30 mm region Are measured with an electron microscope and the average is calculated, so that each dimension relating to the microprotrusions 32, for example, the interval d2 of the microprotrusions 32 and the height H of the protrusions can be specified.

  By the way, in the concavo-convex structure layer 30 shown in FIG. 4, the microprojections 32 are irregularly arranged, but the arrangement of the microprojections 32 may be irregular or regular. However, from the viewpoint of preventing the occurrence of interference patterns, it is preferable that the arrangement of the microprojections 32 is irregular.

<Mesh structure>
Next, the mesh structure 20 will be described. The mesh structure 20 is a mesh-like material that defines a large number of open regions 21. As described above, the mesh structure 20 is made of the conductor 25 that defines the opening region 21, for example, metal. The conductor 25 includes a conductor main body 26 extending in a curved or linear shape. As shown in FIG. 2, the conductor main body 26 of the conductor 25 extends along a valley bottom 34 that is between the minute protrusions 32 in the concavo-convex surface 31 of the concavo-convex structure layer 30.

  Accordingly, each opening region 21 is formed corresponding to the minute protrusion 32 of the concavo-convex structure layer 30, and the opening region 21 is penetrated by the corresponding minute protrusion 32 in the mesh sheet 10. In this mesh sheet 10, the distance d2 (see FIG. 1) between the opening regions 21 can be replaced with the distance d1 (see FIGS. 2 and 3) between the minute protrusions 32. For this reason, the mesh structure 20 can be miniaturized by miniaturizing the uneven surface 31. For this reason, by reducing the distance d1 between the minute protrusions 32, the distance d1 between the opening regions 21 can be reduced, and the line width w2 of the conductor main body 26 of the conductor 25 can be reduced.

  Further, the mesh sheet 10 shown in FIG. 2 includes an uneven surface corresponding to the unevenness of the uneven surface 31 of the uneven structure layer 30. The unevenness of the uneven surface of the mesh sheet 10 is formed by protrusions formed corresponding to the minute protrusions 32 forming the uneven surface 31 of the uneven structure layer 30.

  Such a mesh structure 20 can be formed as follows. First, as shown in FIG. 7A, a material 25 a that forms the mesh structure 20 is attached on the uneven surface 31 of the uneven structure layer 30. The method for attaching the material 25a is not particularly limited, and examples thereof include a vapor phase method (dry process) such as a vacuum deposition method, a sputtering method, an ion plating method, and a CVD method. However, as shown in FIG. 7A and FIG. 6A, the amount of the material 25a attached is such that the material 25a adheres to the uneven surface 31 as a granule without forming a film on the uneven surface 31. Is preferred. For example, when the size and shape of the microprojections 32 of the concavo-convex structure layer 30 is the above-described size and shape as a more preferable range, for example, the film thickness of a material 25a made of a metal material described later is 1 nm to 50 nm. It can be as follows.

  In addition, the film-forming thickness here means the thickness of the film formed when it is assumed that the uneven surface 31 of the uneven structure layer 30 is a flat surface without unevenness. 6A and 7A show a state in which gold is actually deposited on the uneven surface 31 by vacuum deposition with a film thickness of 5 nm.

  As shown in FIG. 6A and FIG. 7A, the material 25 a is granular and adheres on the uneven surface 31. Then, as shown in FIGS. 6A and 7A, when the material 25a is adhered to the uneven surface 31, more material 25a becomes a valley bottom 34 between the two adjacent minute projections 32. It will stick to the top. Then, as shown in FIGS. 5A and 6A, a part of the material 25 a is arranged on the valley bottom 34 formed around the minute protrusion 32 on the uneven surface 31. However, the material 25 a adheres substantially uniformly to portions other than the valley bottom 34 on the uneven surface 31.

  Next, an annealing process is performed on the material 25 a attached on the uneven structure layer 30. In this annealing treatment, the material 25a is not simply heated, but the material 25a is irradiated with xenon flash lamp light or infrared rays. More specifically, light having a wavelength of 200 nm or more and 30 μm or less is irradiated in a planar shape on the uneven surface 31 to which the material 25a is attached. When the material 25a on the concavo-convex surface 31 is sufficiently miniaturized, typically, in the case of nano-order particles, a metal located adjacently by irradiation with xenon flash lamp light or infrared rays. The manufactured material 25a is welded, that is, melted and joined.

  By this annealing process, as shown in FIG. 5 (a), a large number of materials 25a arranged in a line are welded to each other to form openings as shown in FIG. 5 (b). The conductor main body 26 defining the region 21 is formed. Further, as can be understood from FIGS. 6 and 7, the granular material 25a adhering to the portion other than the valley bottom portion 34 of the microprojection 32 is in the form of other granular particles located in the vicinity as the annealing process proceeds. It is welded to the material 25a and approaches the valley bottom 34 side. In this way, a large amount of material 25a gathers on the valley bottom 34 on the uneven surface 31 by the annealing process, and forms the conductor body 26.

  However, not all of the material 25a moves to the valley bottom 34 depending on the degree of annealing treatment. As shown well in FIG. 7B, a part of the material 25a is part of the surface of the microprotrusions 32 between the bottom surface 34 and the top 33 even after the annealing process, It may remain on the top 33. Such a material 25a forms a conductor extension 27 that extends from the conductor body 26 in the mesh structure 20 that is manufactured.

  The conductor extending portion 27 extends on the uneven surface 31 on the surface of the minute protrusion 32 from the valley bottom portion 34 toward the top portion 33. That is, as shown in FIG. 2, the valley bottom 34 of the concavo-convex surface 31 is located on a certain virtual surface on the concavo-convex surface 31, and the conductor extension 27 is shown by a two-dot chain line in FIG. 2. In addition, the conductor main body 26 formed on the valley bottom 34 is along the normal direction to the virtual surface (along the normal direction to the sheet surface of the concavo-convex structure layer 30 (mesh sheet 10)). ), Located in different positions. In other words, in the mesh structure 20, the conductor extension portion 27 faces the opening region 21 in which the portion of the conductor main body portion 26 connected to the conductor extension portion 27 defines and opens. A position shifted from the region 21 in the normal direction to the virtual plane extends. That is, the mesh structure 20 has a three-dimensional structure. Note that the amount, thickness, shape, and the like of the conductor extension 27 can be controlled by the conditions of the annealing process.

  In addition, as the material 25a that forms the conductor 25, a metal material such as gold, silver, copper, platinum, aluminum, chromium, molybdenum, nickel, titanium, palladium, indium, or an alloy thereof is used. Can be used. In particular, from the viewpoint of reducing the line width w2 of the conductor body 26 by depositing the material 25a on the uneven surface 31 in a granular form, one or more of gold, silver, copper, platinum, and alloys thereof are used as the material. As for 25, it is suitable to make it adhere on uneven surface 31 by a vacuum evaporation method.

  In the mesh structure 20 as described above, plating, for example, electroless plating may be performed after the annealing treatment from the viewpoint of reducing surface resistance and imparting high conductivity. As a material used for plating, for example, one or more of copper, aluminum, chromium, nickel, and alloys thereof can be used.

  Moreover, it is also possible to take out the mesh structure 20 from the mesh sheet 10 according to a use. For example, in the mesh sheet 10, when the transparent base material 15 and the mesh structure 20 are made of a transparent resin, the transparent base material 15 and the mesh structure 20 are dissolved from the metal by chemical or physical dissolution. Only the mesh structure 20 can be taken out.

<Effects of mesh sheet and mesh structure>
The mesh structure 20 as described above is formed from a conductor 25 having conductivity. Therefore, the mesh structure 20 can exhibit some function related to conductivity.

  The mesh structure 20 has a stitch shape that defines the opening region 21 and is light-transmitting. In particular, the mesh structure 20 is very fine. For example, the average line width w2 of the conductor main body 26 of the conductor 25 may be 5 nm or more and 500 nm or less, and the average distance d2 between the adjacent opening regions 21 may be 1000 nm or less. Such a conductor main body 26 of the mesh structure 20 generally cannot be resolved by human eyes. That is, the mesh structure 20 described here can be effectively avoided from being visually recognized. Thereby, it becomes possible not only to improve the permeability of the mesh structure 20 but also to effectively prevent the following problems caused by the visual recognition of the mesh structure 20.

  First, since the line width w2 of the conductor 25 constituting the mesh structure 20 is sufficiently thin, it is possible to prevent the occurrence of glare and shading unevenness. The shading unevenness is considered to be a phenomenon in which the transmittance is locally reduced due to the nonuniformity of the density distribution of the conductor 25 and the nonuniformity of the line width of the conductor 25 in the pattern of the mesh structure 20. Yes. On the other hand, the glare is considered to be a phenomenon in which the amount of reflected light locally increases due to the non-uniformity of the density distribution of the conductors 25 in the pattern of the mesh structure. According to the mesh structure 20 described here, since the average line width of the conductor 25 is reduced to 500 nm or less, the line portion 12 itself of the conductor 25 is sufficiently invisible, and the shading is uneven. It is difficult to see the stick.

  In addition, when a mesh structure is disposed on a display panel capable of color display, a specific pixel may be covered with a conductor of the mesh structure. As an example, when white display is performed with typical pixels including a red sub-pixel, a green sub-pixel, and a blue sub-pixel, when the red sub-pixel is covered by the conductor of the mesh structure, the white sub-pixel is displayed instead of white, When the green sub-pixel is covered, it is displayed in magenta instead of white, and when the blue sub-pixel is covered, it is displayed in yellow instead of white. Such a phenomenon is referred to as flickering and reduces color reproducibility. On the other hand, according to the mesh structure 20 described here, the average line width of the conductor 25 is set to 5 nm or more and 500 nm or less. Therefore, the conductor 25 of the mesh structure 20 does not block a specific pixel. Thereby, the color reproducibility of the display device is not deteriorated.

  Similarly, since the mesh structure 20 is miniaturized, moire that can occur when superimposed on other members can be effectively made inconspicuous. In particular, for example, when the mesh structure 20 is miniaturized so that the average of the line width w2 of the conductor main body 26 is 5 nm or more and 500 nm or less and the average of the distance d2 between the adjacent opening regions 21 is 1000 nm or less. The moire can no longer be visually recognized when the mesh structure 20 is superposed on another member regardless of the regularity of the arrangement of the opening regions 21.

  Moire is a phenomenon in which bright and dark streaks become visible, and the regularity (periodicity) of the pattern of the mesh structure and the regularity of the pattern of other members overlaid on the mesh structure (for example, a display device) This is caused by interference with the regularity of the pixel arrangement. Therefore, the moire can be effectively made inconspicuous by adjusting the arrangement pitch of the opening regions 21 of the mesh structure 20 to a pitch that does not cause interference with the regular pattern of other members. On the other hand, in the mesh structure 20 described here, in addition to the line width of the conductor 25 being set very narrow, the distance d2 between the two adjacent opening regions 21 is also set very small. Therefore, moire that can occur in combination with members that have been problematic until now, for example, moire that can occur in combination with a typical display panel in which sub-pixels are arranged at several tens of μm, is effectively conspicuous. Can be eliminated. In addition, in the illustrated example, the arrangement of the opening regions 21 of the mesh structure 20 does not have a periodic pattern. Therefore, the generation of moire can be suppressed extremely effectively.

  Further, in many cases, the mesh structure 20 is used while being supported on a transparent substrate. On the other hand, the mesh structure 20 can be formed using the uneven surface 31 of the uneven structure layer 30. Specifically, the conductor main body 26 of the conductor 25 forming the mesh structure 20 extends on the valley bottom 34 of the minute protrusion 32 forming the uneven surface 31. The concavo-convex structure layer 30 functions as a moth-eye structure when the fine protrusions 32 are provided at a distance d1 that is equal to or shorter than the shortest wavelength in the visible light band. That is, the concavo-convex structure layer 30 that supports the mesh structure 20 can exhibit an extremely excellent antireflection function, and thereby can exhibit high transmittance while preventing reflection.

  The mesh sheet 10 is related to the conductivity of the mesh structure 20 by virtue of the excellent visible light transmittance of the mesh structure 20 itself and the excellent visible light transmittance due to the excellent antireflection function of the uneven structure layer 30. While exhibiting some kind of function, it exhibits extremely excellent visible light transparency. Applying the concavo-convex structure layer 30 having an extremely excellent antireflection function as a support for the mesh structure 20 having electrical conductivity and excellent visible light transmission is different from conventional ones or has an excellent effect. In other words, it can be said that it is possible to achieve remarkable effects that exceed the range predicted from the technical level.

  On the other hand, since the mesh structure 20 is extremely miniaturized, the specific surface area of the mesh structure 20 alone is very large. For this reason, even when the mesh structure 20 is taken out from the mesh sheet 10 and the mesh structure 20 is used separately from the uneven structure layer 30, the mesh structure 20 provides excellent operational effects. For example, when the mesh structure 20 is used as a catalyst carrier, it becomes possible to carry a large amount of a refined catalyst and promote a catalytic reaction resulting from the carried catalyst. In particular, when the conductor 25 has a three-dimensional structure including the conductor main body portion 26 and the conductor extension portion 27 extending from the conductor main body portion 26, the catalytic reaction is promoted. Becomes more prominent.

  Here, the present inventors introduce an example of the result of actually producing a mesh sheet and measuring the transmittance.

First, the mesh sheet formed an uneven structure layer by shaping an ionizing radiation curable resin using an original plate, and then produced a mesh structure on the uneven structure layer.
An original plate for producing the concavo-convex structure layer was produced as follows. After polishing a rolled aluminum plate having a purity of 99.50% so that the surface has an irregular shape with a 10-point average roughness Rz of 30 nm as a small undulation and a period of 1 μm as a large undulation, a 0.02 M aqueous solution of oxalic acid is used. In the electrolytic solution, anodization was performed for 120 seconds under the conditions of a formation voltage of 40 V and 20 ° C. Next, as a first etching process, an etching process was performed for 60 seconds with the electrolytic solution after anodization. Subsequently, as the second etching treatment, a pore size treatment was performed with a 1.0 M phosphoric acid aqueous solution for 150 seconds. Furthermore, the said process was repeated and these were added and implemented 5 times in total. As a result, an anodized aluminum layer having fine irregularities formed on the aluminum substrate was formed. Finally, a fluorine-based mold release agent was applied and the excess mold release agent was washed to obtain an original plate for forming a fine uneven layer. In addition, the fine uneven shape formed in the aluminum layer has an average distance between adjacent micropores of 100 nm, an average depth of 200 nm, and a large number of micropores that are gradually reduced in the depth direction. It was a shape.

Using the original plate thus produced, an uneven structure layer was produced by the following method. First, a resin composition for forming an uneven structure layer for forming an uneven structure layer includes 20 parts by weight of dipentaerythritol hexaacrylate (DPHA), 70 parts by weight of Aronix M-260 (manufactured by Toagosei Co., Ltd.), hydroxyethyl acrylate It was prepared by mixing 10 parts by weight and 3 parts by weight of Lucillin TPO (manufactured by BASF) as a photopolymerization initiator. Thereafter, the resin composition for forming an uneven structure layer is coated and filled so that the fine uneven surface of the original plate for forming an uneven structure layer is covered and the thickness of the fine uneven layer after curing is 20 μm, and transparent After a 80 μm thick triacetyl cellulose (TAC) film (Fuji Film Co., Ltd.) was bonded as a base material at an angle, the bonded body was pressed with a rubber roller under a load of 10 N / cm ² . After confirming that the uniform composition was applied to the entire original plate, the resin composition for forming the concavo-convex structure layer was cured by irradiating ultraviolet rays with an energy of 2000 mJ / cm ² from the transparent substrate side. Next, it peeled from the original plate and the laminated body (intermediate sample A) of the transparent base material and the uneven structure layer was obtained.

  Then, on the uneven surface of the uneven structure layer of the intermediate sample A, using a vacuum deposition apparatus (VPC-410, manufactured by ULVAC, Inc.), the same area as the region on the uneven surface in a plan view with a degree of vacuum of 8 × 10E-6 Torr. When the film was formed on the surface of the lithographic material, the product of the intermediate sample B was obtained by vapor-depositing gold with an equivalent film thickness of 5 nm on a flat surface that would be 5 nm. The color tone observed visually was blue-purple.

  Next, the article of sample B (mesh sheet) was obtained by annealing the article of intermediate sample B with an energy of 1251 J using a flash lamp annealing apparatus (SINTRON 2000, manufactured by XENON). The color tone observed visually was reddish purple. 6 is an image obtained by mapping heavy elements with SEM reflected electrons for the intermediate sample B and the sample B, and FIG. 7 is a STEM image for the intermediate sample B and the sample B. Gold nanoparticles were formed on the article of intermediate sample B. On the other hand, a fine gold wire was formed on the article of Sample B.

  Similarly to the intermediate sample B, the article of the intermediate sample C was obtained by changing gold to silver. The color tone observed visually was yellow. The article of sample C (mesh sheet) was obtained by annealing the article of intermediate sample C with an energy of 1501 J using a flash lamp annealing apparatus (SINTRON 2000, manufactured by XENON). The color tone observed visually was pale yellow.

<Evaluation of antireflection performance>
The reflectance of each produced sample was evaluated. The transparent substrate side of the article obtained in each sample example was bonded to a black acrylic plate (Mitsubishi Rayon, product name Acrylite) via an adhesive (Panak, product name Panaclean PDR5) The reflectance was measured with a spectroscope (manufactured by JASCO, spectroscope V-7100 and automatic absolute reflectance measurement unit VAR-7010). The results are shown in FIG. As understood from the results of FIG. 8, the uneven surface (intermediate sample A) of the uneven structure layer exhibited an extremely excellent antireflection function. Moreover, the reflectance of the uneven surface (intermediate samples B and C) on which the metal is deposited and the reflectance of the uneven surface (samples B and C) on which the mesh structure is formed are also about 0.3%, which is extremely low. It was value. That is, the uneven surface (intermediate samples B and C) on which the metal is deposited and the uneven surface (samples B and C) on which the mesh structure is formed are compared with the antireflection film composed of a low refractive index layer that is widely used. Thus, it had a remarkably excellent antireflection function.

<Evaluation of transmittance>
The transmittance of each prepared sample was evaluated. By measuring with a spectroscope (manufactured by Shimadzu Corporation, spectrophotometer UV-3100PC), an average value of transmittance (%) at wavelengths of 380 to 780 nm of the articles according to each sample was obtained. The transmittance of the intermediate sample A is 95%, the transmittance of the intermediate sample B is 66%, the transmittance of the sample B is 67%, the transmittance of the intermediate sample C is 62%, and the intermediate sample C The transmittance of was 69%.

<Specific application example of mesh sheet and mesh structure>
Next, application examples of the mesh structure 20 and the mesh sheet 10 will be specifically described. As an example, the mesh structure 20 and the mesh sheet 10 are grounded and shielded from electromagnetic waves, an electrode for a touch panel sensor of a touch panel device, an antenna having visible light permeability, a collector electrode of a solar cell, dew condensation It can be used as a heating electrode for prevention.

  First, as shown in FIG. 9, the mesh structure 20 and the mesh sheet 10 include a television receiver, various measuring devices and instruments, various office devices, various medical devices, computing devices, telephones, electric signs, Incorporated as an electromagnetic shielding material in image display devices such as plasma display (PDP) devices, cathode ray tube display (CRT) devices, liquid crystal display devices (LCD), and electroluminescent display (EL) devices used in display units of game machines Can be.

  In the example illustrated in FIG. 9, the image display device 40 includes an image forming device (display panel or display unit) 41 that can form an image, and a stacked body 45 that is disposed on the light output side of the image forming device 41. Have. Therefore, the light emitting surface of the stacked body 45 forms the display surface (light emitting surface) 40 a of the image display device 40, and the observer observes the image formed by the image forming device 41 through the stacked body 45. Become. A mesh sheet 10 as an electromagnetic wave shielding sheet is incorporated in the laminated body 45. The mesh structure 20 of the mesh sheet 10 extends and spreads in a region where an image of the image forming apparatus 41 is formed. While this mesh structure 20 can effectively shield electromagnetic waves, it is difficult to be visually recognized by setting its line width narrow. For this reason, generation | occurrence | production of malfunctions, such as a moire resulting from the visual recognition of the mesh structure 20, a shading unevenness, and flickering can be prevented effectively. In addition, although functional sheets, such as an antireflection sheet and a louver, are appropriately incorporated in the laminated body 45, generation of moire between the mesh structure 20 and other functional sheets is effectively prevented. become.

  In addition, for electromagnetic shielding applications such as windows for buildings such as houses, schools, hospitals, offices, stores, etc., windows for vehicles such as vehicles, aircraft and ships, windows for various household appliances such as microwave oven windows, etc. It can be used. In this example, the window material that supports the mesh structure 20 as the electromagnetic wave shielding material may form the transparent base material 15 in the mesh sheet 10, or the window material may be another part of the mesh sheet 10. May be configured. In this example, it is possible to effectively prevent the generation of moire between the mesh door 20 and the screen doors and curtains arranged on the window material, and the shading unevenness, glare and flickering. It is also possible to effectively prevent discomfort caused by the above.

  Next, an example in which the mesh structure 20 is applied to the touch panel sensors 51 and 52 of the touch panel device 50 will be described with reference to FIG. FIG. 10 discloses a touch panel device 50 including touch panel sensors 51 and 52. The illustrated touch panel device 50 is configured as a projected capacitively coupled touch panel device, and includes a first touch panel sensor 51 and a second touch panel sensor 52 each having an electrode 55 formed on a transparent substrate 35. ing. The touch panel device 50 is arranged on the image forming apparatus. The first and second touch panel sensors 51 and 52 include an active area Aa1 facing an area where pixels of the image forming apparatus are arranged, and an active area. And an inactive area Aa2 around Aa1. The electrode 55 includes a detection electrode 60 that is located in the active area Aa1 and used for position detection, and an extraction electrode 70 that is connected to the detection electrode 60 and located in the inactive area Aa2.

  As shown in FIG. 10, each detection electrode 60 is connected to a large number of mesh structures 20 arranged at intervals in the longitudinal direction and connection conductors 61 connecting two adjacent mesh structures 20. And have. Each detection electrode 60 extends linearly within the active area Aa <b> 1 by the mesh structure 20 and the connecting conductor 61. The width of the region where each detection electrode 60 is arranged is thicker in the portion where the mesh structure 20 is provided. Each detection electrode 60 included in one touch panel sensor 51, 52 intersects with a large number of detection electrodes 60 included in the other touch panel sensor 52, 51. As shown in FIG. 10, the mesh structure 20 of one touch panel sensor 51, 52 is on the detection electrode 60 between intersections of two adjacent detection electrodes 60 of the other touch panel sensor 52, 51. Has been placed.

  In the touch panel device 50, the mesh structure 20 of the touch panel sensors 51 and 52 is disposed on an area where the pixels of the image forming apparatus 41 are arranged. The mesh structure 20 functions as the detection electrode 60 due to its excellent conductivity, and can prevent the occurrence of moire, shading unevenness, glare and flicker as described above.

  The shape of the electrode 55 shown in FIG. 10 is merely an example, and various changes can be made. Further, the mesh structure 20 and the mesh sheet 10 are not limited to the projected capacitive coupling type touch panel device, and can be applied to various types of touch panel devices.

  As another application, the mesh structure 20 and the mesh sheet 10 function as an antenna supported by a window. Moreover, the mesh structure 20 and the mesh sheet 10 function as a heat generation electrode for preventing condensation supported by a window. In these examples, the window material may form the mesh sheet 10 and the transparent base material 15 of the mesh sheet 10, or the window material may constitute another part of the mesh sheet 10. In these examples, it is possible to effectively prevent the occurrence of moiré between the mesh door 20 and the screens and curtains arranged on the windows, and the shading, glare and Receiving discomfort due to flickering is also effectively prevented.

<< Addition, modification, other >>
Various additions and changes can be made to the above-described example. Hereinafter, an example of modification will be described.

  In the example described above, the transparent base material 15 and the uneven structure layer 30 of the mesh sheet 10 are formed as separate layers. Such a mesh sheet 10 can be produced by forming an uneven structure layer 30 formed by molding an ionizing radiation curable resin on the transparent substrate 15. On the other hand, the mesh sheet 10 may further include a layer other than the mesh structure 20, the concavo-convex structure layer 30, and the transparent substrate 15, or the concavo-convex structure layer 30 may be produced by injection molding or extrusion molding. Thus, the transparent substrate 15 may be omitted.

  Further, the uneven surface 31 of the uneven structure layer 30 may be formed as a hard coat layer for improving the scratch resistance. This hard coat layer may be formed as a thin film. Alternatively, from the viewpoint of improving the scratch resistance, the concavo-convex structure layer 30 may contain a slip agent. Furthermore, from the viewpoint of preventing deterioration due to ultraviolet rays, the mesh sheet 10 may contain an ultraviolet absorber.

  In addition, although the some modification with respect to the example mentioned above was demonstrated above, naturally, it is also possible to apply combining several modifications suitably.

DESCRIPTION OF SYMBOLS 10 Mesh sheet 15 Transparent base material 20 Mesh structure 21 Opening area | region 25 Conductor 25a Material 26 Conductor main-body part 27 Conductor extension part 30 Uneven structure layer 31 Uneven surface 32 Microprotrusion 33 Top 40 Image display apparatus 40a Display surface 41 Image forming apparatus, display panel, display unit 45 Laminate body 50 Touch panel device 51 First touch panel sensor 52 Second touch panel sensor 55 Electrode 60 Detection electrode 61 Connection lead 70 Extraction electrode

Claims (7)

An uneven structure layer having an uneven surface formed by minute protrusions;
And a mesh structure including a conductor provided on a valley bottom portion between the minute projections on the uneven surface. The average line width of the conductor of the mesh structure is 5 nm or more and 500 nm or less,
The mesh sheet according to claim 1, wherein an average interval between adjacent microprotrusions is 1000 nm or less.   The mesh sheet according to claim 1 or 2, wherein the minute protrusions are provided at intervals that are equal to or shorter than the shortest wavelength in the visible light band.   The mesh sheet according to any one of claims 1 to 3, wherein the conductor is also provided on a portion of the uneven surface other than the valley bottom. Comprising a conductor defining an open area;
The average line width of the conductor is 5 nm or more and 500 nm or less,
The mesh structure whose average of the space | interval of an adjacent opening area | region is 1000 nm or less. A conductor body located on a virtual plane and defining an open area;
A conductor extension extending from the conductor body, and
The conductor extension part is a position facing a normal direction to the virtual plane with respect to an opening region defined by a portion of the conductor main body part connected to the conductor extension part. Extending the mesh structure. The average line width of the conductor body is 5 nm or more and 500 nm or less,
The mesh structure according to claim 6, wherein an average interval between adjacent opening regions is 1000 nm or less.